A study on replay attack and anti-spoofing for text-dependent speaker verification

Replay, which is to playback a pre-recorded speech sample, presents a genuine risk to automatic speaker verification technology. In this study, we evaluate the vulnerability of text-dependent speaker verification systems under the replay attack using a standard benchmarking database, and also propose an anti-spoofing technique to safeguard the speaker verification systems. The key idea of the spoofing detection technique is to decide whether the presented sample is matched to any previous stored speech samples based a similarity score. The experiments conducted on the RSR2015 database showed that the equal error rate (EER) and false acceptance rate (FAR) increased from both 2.92 % to 25.56 % and 78.36 % respectively as a result of the replay attack. It confirmed the vulnerability of speaker verification to replay attacks. On the other hand, our proposed spoofing countermeasure was able to reduce the FARs from 78.36 % and 73.14 % to 0.06 % and 0.0 % for male and female systems, respectively, in the face of replay spoofing. The experiments confirmed the effectiveness of the proposed anti-spoofing technique.